There is known a vibratory linear actuator that includes a stator, a plurality of movable members arranged in parallel, an electromagnet arranged in the stator, a plurality of permanent magnets arranged in the movable members, a support unit for movably supporting the movable members so that the magnetic pole surface of the electromagnet can oppose the magnetic pole surfaces of the permanent magnets with a gap left therebetween, the movable members being caused to vibrate by supplying an electric current to the electromagnet (see Japanese Patent Laid-open Publication No. 2005-354879).
In the vibratory linear actuator, the support unit and the plurality of movable members are connected to each other by thin elastic pieces and are molded into an integral body with a synthetic resin for the purpose of reduction in size. The support unit is divided into two support portions along the reciprocating vibration direction of the movable members. The stator is interposed between the two support portions for reduction in height dimension.
With the vibratory linear actuator, the electromagnet is arranged in the stator and the permanent magnets are arranged in the movable members. The movable members are reciprocatingly vibrated in opposite phases. Therefore, a torsional force is always applied to the support portions, which means that the actuator is susceptible to a change in the gap size between the permanent magnets and the electromagnet. In view of this, the synthetic resin-made base of the stator and the support portions are firmly coupled together by a plurality of screws in an effort to stabilize the gap size.
However, not only such a screw coupling structure is costly but also additional screws are needed to fix the vibratory linear actuator to the housing of an electric razor.